Method and system of heating



June 3, 1941'. G. J. BELKNAP METHOD AND SYSTEM OF HEATING Filed May 26,1938 wlw INVENTOR 1 5'? f1 ATTORNEY Patented `lune 3, 1941 UNTED STTSATENT GFFECE- METHD AND SYSTEM F HEATING George J. Belknap, Fairfield,fConn., assigner to The Belknap Manufacturing Company, Bridgeport,Conn., a corporation of Connecticut Appiicaufm May 26, 1938, serial No.210,140

, (Cl. 23T-63) This invention relates to heating systems for 13 Claims.

building interiors in which a iiuid medium is circulated through loopsof pipe or conduit Yconnecting with radiators located in diierent roomsof the building and connected with acommon heating apparatus usually inthe basement. The y, invention further relates to methods for invertingthe proportional amounts of water or other fluid medium permitted to owthrough any two radiators in such a system.

The radiators in a system of this kind which are nearest the heatingapparatus commonly i' tend to receive a greater share of the fluidmedium iiowing from the heating apparatus than do the radiators whichare relativelyrrernote therefrom. This condition cannot satisfactorilybe taken care of by any established relationship of pipe sizes indifferent parts of the system because the amount of heat which theradiators are designed to furnish in different rooms vmay itself need tobe changed to accord with some.

change in the use .to which theroom is put or to accord with varyingdifficulty in heating a given room at diierent seasons of the year.There are other and unpredictable factors in the heating of buildingswhich may call for change Y in the proportionate distribution of theheat conveying medium or fluid to the respective radiators in the systemwhen all radiators are being supplied by a common heating apparatusthrough a full capacity opening of their respective control ,l

valves.

As the individual radiator control valves may be fully closed or openedto selective degrees up to their full port capacity by the occupant of agiven room, this selective throttling function of an ordinary valvecannot successfully be made use of to insure desired balance ordistribution of heat throughout the system as a whole. It

vhas been proposed to install choke battles within the pipes or conduitsfor reducing the flow ofA the system balance is required in practicemakes.

such operations as these too laborious and time consuming to befeasible, and also the system must be deprived of heat While the changeis being made.

One object of the present improvements is to provide in a heating systemof the character described devices to determine the proportionate now cithe heating medium throughdierent radiators in such form that thechanging of such device or devices requires no uncoupling of pipeconnections and avoids the necessity for draining water or other heatconveying uid from the system.

Another object is to install such devices in such a system in a form tobe unchangeable by any means available to the occupant of a room inwhich only a single radiator controlvalve is located.

Another object is to provide such devices in such form that any changeof one of the devices must require the simultaneous interchanging of twosuch devices between any two diierent points in the system in theabsence of extra parts not originally incorporated or operativeV in thesystem.

Another object is to incorporate such devices as concealed but removableinserts in the bodies or casings of control valves governing apluralityl of radiators in the system.

Another object is to incorporate at least two such devices respectivelywithin the casings of at least two valves having operating handles andother external parts of such nature, and so affected in their operationby such devices, that it cannot be known to the ordinary user of eitherof the valves what flow limiting eiect is produced upon the valve by thepresence of the device therein, or in fact that any extraordinary flowreducing device is present within the structures ci the valves.

A further object is to provide stop devices interchangeably installablewithin the casings of dilierent valves in the system in a manner tocooperate with the port control member in each valve and which stopdevices shall be so differently constructed that they restrict the portopenings to diierent maximum capacities in different valves.

A still further object is to practice in a system of the characterdescribed a novel method of inverting the proportional amounts of` Wateror other heat conveying medium permitted to flow through any tworadiators in the system when the control valves of such radiators areapparently opened `to, their fullest extent and Without of necessityanecting theA proportional distribution of Water to such radiators whenthe said valves are less than fully opened.

A still further object is to practice in a system of the characterdescribed a novel method of inverting the relative freedom of water toiiow through two radiator control valves in the system which consists inremoving from each ofv said valves a concealed part of its structuredetermining the maximum size of port which may be opened through thevalve and reinstalling each of said parts in the structure of the othervalve.

A still further object is to provide a hea-ting system incorporatingradiators and valves in which a seemingly full degree of openingmovement of the handles of all the valves controlling the differentradiators in the system may, indiscernably tothe user of the valve, bemade to result in a smaller actual size of water flow passage beingopened through some valves of the system than is opened through othervalves of the system, so that relatively differing distribution of wateriiow tc different radiators will occur when the handles of all of theradiator valves are turned to their limit open position.

A still further object is to make possible such change in thecharacteristic of port opening performance of any valve responsive to anunreduced full range of opening movement of its operating handle whilethe entire system, including portions of the valve interior, is rllledwith water under greater than atmospheric pressure and Withoutpermitting escape of water in the process.

These and other purposes of the present improvements will appear moreclearly from the following description of means by which they may beaccomplished in which description reference is had to the accompanyingdrawing, wherein:

Fig. 1 represents diagrammatically a typical relationship of househeating radiators which may be located in diierent rooms and on diierentfloor levels while connected in a suitable system of pipes or conduitsleading from and back to a common form of heating apparatus in thebasement which if desired may include apparatus for accelerating thecirculation of water or other heating medium through the system.

Fig. 2 is a plan view of one of the radiator control valves in Fig. 1indicating diagrammatically'a limited range of turning movement for itscontrol handle.

Fig. 3 is a plan view of a diierent one of the radiator control valvesin Fig. 1 indicating a differently located but similar range of turningmovement for its control handle.

Fig. 4 is an enlarged view taken in central vertical section through thevalve of Fig. 3 looking in the direction of the arrows Iand showing thevalve detached from its pipe connections with itsports fully open.

Fig. 5 is a still further enlarged and perspective view of a removablestop bushing which may interchangeably be inserted within the structureof either of the valves of Figs. 2 and 3.

Fig. 6 is a corresponding view of a differently constructed removablestop bushing which may interchangeably be inserted within the structureof either of the valves of Figs. 2 and 3.

Fig. '7 is a fragmentary view taken in section through a valvecontaining the stop bushing of Fig. 5 on the plane 'I-'l in Fig. 4looking in the direction of the arrows and showing'the ports of thevalve as fully open as is permitted by the stop bushing.

Fig. 8 is a view similar to Fig. 'l showing the ports of the same valveas related when the handle has been turned to stop limited position invalve closing direction.

Fig. 9 is a fragmentary view taken in section through a similar valvecontaining the stop bushing of Fig. 6 on the plane 1 -I in Fig. 4looking in the direction of the arrows and showing the ports of thevalve as fully open as is permitted by the stop bushing.

Fig. 10 is a view similar to Fig. 9 showing the ports of the same valveas rela-ted when the handle has been turned to stop limited position invalve closing direction.

Figs. 11, 12, 13 and 14 are views taken in section on the common planeII-II in Fig. 4 looking in the direction of the arrows and show the stoplug carried by the valve stem in its several relations to the stopshoulders of the two bushings of Figs. 5 and 6 correspondingrespectively to the positions of the ports shown respectively in. Figs.'l to 10.

While the present improvements may be incorporated in either a steamheating or a water heating system, they are believed to aiord for therst time an apparatus capable of successfully equalizing thedistribution of heat to widely separated radiators in a water heatingsystem wherein circulating water is confined at greater than atmosphericpressure and completely lls the conduits and radiators of the system.Fig. l is therefore drawn to represent such a system in which someradiator I0 may belocated at a high point, such as on the top iioor I4of a building, and connected to an intake conduit II containing thevalve I2 and to the usual return conduit I3. Another radiator I5 at alower point in the system may connect to the same intake conduit II bymeans of a short stretch of branch pipe I6 inV which is located thevalve IT, and may connect to the return conduit I3 through the shortbranch pipe I8. Thus pipes II and I3, connecting respectively to thesupply main I9 at the elbow 20 and to the return main 2I at the T 22,serve as supply and return lines for both radiators, yIIJ and I5.

The supply main I9 leads from the top of the usual water jacket (notshown) contained in any form of heater unit or apparatus 23 located inthe basement of a building and adapted to burn coal, oil, gas or otherkind of fuel, while the return main 2l may extend to a uid urge pump 24operated by any suitable means such as an electric motor 25, from whichpump the pressure line 25 leads back to the water jacket in heater unit23. A pump such as 24 is often omitted, leaving the water to becirculated as a mere consequence of raising its temperature in theheater 23. Such pump, employed for the purpose of speeding up thecirculation of water. is apt to aggravate the tendency toward unequaldistribution of heat to various radiators. Whether or'not a Ipump isused, this troublesome condition 'is successfully remedied by the pre"-ent invention.

A Ythird radiator 2'! lis shown on a common level with radiator I5 andis located in a separate loop of conduit which includes the supply pipe28connecting to the supply main I9 at the T-coupling 29 and containingthe valve 33, and which further includes the return pipe 3| connectingto the return main 2| at the T-coupling The distance through which`water heated in the unit 23 must travel to reach radiator 21 ismaterially less than the distance it must travel structed bushingsinterchangeably in various to reach radiators l or l5. Hence radiator 21will tend to receive a greater portion of the ow of hot water fromheater 23 than will the other radiators.

One example of means, which according to the present invention may beemployed for attaining regulatable or equalized distribution of heatthroughout the system, is inclusive of the structures shown in Figs. to14 inclusive. In Fig. 4 the valve body or casing 33 is provided withthreads 34 for connection with the supply pipe and with threads 35 forconnection to the radiator. This casing and all other parts of the valvewith the exception of the stop bushings of Figs. 5 and 6 are preferablyalike in each of the valves l2, I1 and 3U. The casing comprises a hollowstructure whose portions may or may not form an integral castingl andwhose top threaded neck portion36 receives the usual hollow packing nutor cap 31 containing and adapted to squeeze the usual packing material38 against the valve stem 39 to effect a fluid tight seal whilepermitting the valve stem to rotate. Stem 39 extends through an aperturein cap 31 in the usual mannerand carries fast to its fiatted bottom end40 the roof wall 4l of a turnable, cylindrical gate 42 secured in iixedrotative relation to the stem by the nutl 43 having threaded engagementwith the stem and forcing the gate wall 4| solidly against the stemshoulders formed by the flats thereon.

The cylindrical gate 42 is hollow and is open at its bottom end.- Itslateral wall contains the port aperture 44 which is turnable to and fromregister with the lateral passage 45 in casing 33 leading toward theradiator. Gate 42 bears rotatively against the cylindrical surface ofthe casing interior and is held upwardly in its position shown in Fig. 4by the peripheral flange 46 on the valve stem 39 whose downward thrustis borne by a cross wall-41 apertured to-pass the stem and counterboredfrom the top for nesting the flange 46 of the stem.

A ring 48 of resilient packing material such as rubber or suitablecomposition, reinforced if desired by a fibre or fabric layer or facing,surrounds stem 39 between cross wall 41 and the roofwall 4I of gate 42and may be pressed .upwardly against cross wall 41 by a ring-like ridge49 projecting above the otherwise flat roof wall 4I.l Ridge 49 surroundsthe valve stern and 1s radially spaced therefrom and from the innercylindrical surface of the valve casing. By this `construction a fluidtight seal is produced at a point in the valve casing which -precludesthe water or other heating medium controlled by the valve, even if underconsiderable pressure, from reaching the bearing of stem 39 in crosswall 41 and escaping therethrough.

Above cross Wall 41 the neck portion 35 of the valve'casing is bored toform-a cylindrical pocket which may contain either of the stop bushingsof Figs. 5 and 6. These bushings are examples of differently constructedstop devices which for the novel pur-poses of this invention may be im-`mured within the valve structure for determining the maximum range ofturning movement, as well as the positive location of the extreme orlimit positions of valve stem 39 in relation to the valve casing, andhence of port `44 in relation yto the lateral passage 45. According tothe present invention, the stop bushings in different valves differ inconstruction but not in a manner to prevent the insertion of thesedifferently convalve casings of like construction.

Referring more particularly to the stop bushing 50 of Fig. 5 and to thedifferently constructed stop Abushing 5l of Fig. 6, these bushings maybe alike in every respect except that the circumferential relationshipof laterally projecting fins 52 to shoulders 54 and 55 on bushing 55differs from the circumferential relationship of like projecting fins 53to stop shoulders 54 and 55 on bushing 5I. Shoulders 54 and 55 areformed by the similarly cut away -portion of the cylindrical wall ofbushing 55 and bushing 5l, which provides room above the cross wall 41of the valve casing for the sweep of a stop lug 55 xedly carried by thevalve stem slightly above flange 46 thereon. Stop lug 55 is therebyadapted to abut against bushing shoulder54 in the fully closed positionof stem 39 and of its fixedly carried operating handle 51, while thesame lug will abut against bushing shoulder 55 in the fully openposition of stem 39 and handle 51.

Each of bushings 50 and 5I is freely slidable lengthwise of the valvestem and aord bearing therefor. The fins 52 of bushing 50, and in likemanner the iins 53 of bushing 5I, are freely slidable vertically insplines or keyways broached or otherwise produced in the inside face ofthe neck portion 36 of the casing but fit these splines in a way to lockthe bushing against rotative movement relative to the casing. Preferablyneither the splines 58 nor the fins 52 and 53 are in diametricalalignment so that bushings 53 and 5I can each be inserted in only onerotative position relative to the casing.

It is shown in Fig. 4 that the top end of bushing 5i) or 5l whichincludes the circumferential groove 59 projects above the top end of theneck portion 36 of the casing. This top end of the bushing becomesembedded in the packing material 38 of cap 31 when the latter is screweddown firmly on the casing neck 36 and this packing material is squeezeddownwardly against both the top of the 'bushing and the top of thecasingneck thereby sealing all cracks atthe juncture thereof. The bushingisthereby retained in the hollow of the casing neck with its bottom end6l] seated firmly against the toprof the cross Wall 41 of the casing.When the stop bushing is to be removed, valvehandle 51 is released fromits squared engagement with the top end of stem 39 by removing screw 6|after which the handle can be removed from the valve stem. Packing nut31 Will be unscrewedfrom the casing neck 36 during which operation thestop bushing 50 or 5l will separate from packing 38 because the latterturns with the cap while the former is kept from turning by its lockedfins 52 or 53. When the cap 31 and packing 38 are removed by liftingthem o over the top end of the valve stem, the stop bushing is left withits grooved top Vend projecting from the casing neck and may easily bepried upwardly and lifted out of the valve casing and is free to slideupwardly on the valve stem and likewise be removed from the top thereof.A different stop bushing may now be inserted within the valve casing andthe parts restored by a reversal of the operations described.

Having described the structural features of differently constructedstopdevices and the manner inwhich they may be installed interchangeablyforcooperation with the port control member of otherwise similar valvemechanisms, the cooperation' of these structures, devices and mechanismsin a heating system containinga plurality of valves can be explained.

In Fig. 1 by way of example it may be assumed that radiator l isinstalled in a building to heat a little-used room while radiator 21 maylbe depended upon to supply heat for a constantly used room whenever theheating system is in operation. For the purpose of sacrificing the flowof the heating medium through radiator I0 in favor of a dependablesupply of the heating Ymedium to radiator 21, valve l2 is equipped withthe stop bushing 5I which limits the maximum capacity of the portopening to that shown in Fig. 9 when the valve handle is turned to itsopen limit position, while valve 30 is equipped with the stop bushing 55which permitsthe greater opening through port 44 to passage 45 shown inFig. '7. Occasion arises for the little-used room to be constantlyoccupied and it is decided vthat in the characteristic performance ofthe system as a whole, heat can best be spared from radiator 21 toinsiu'e a greater and more dependable supply of the heating medium toradiator I0, Thereupon the engineer in charge of the heating plant willremove bushing 5I from valve l2 and install it in valve 30 at the sametime transferring bushing 5D from valve 30 to valve l2 in the mannerhereinbeiore described. Valve l2 may now be opened to the full extent ofthe capacity of port 44 as shown in Fig. 7 while valve 30 will berestricted to the less maximum capacity Of DOTT' opening shown in Fig.9.

This single example of a practical use for the present improvements in aheating system is but illustrative of a great many occasions whichconstantly arise for varying the distribution of the heating medium todifferent radiators. In systems incorporating many radiators normallysupplied by a common heating plant working at normal capacity, areversal of any two stop devices such as the bushings 50 and 5I betweenany two radiator control valves will involve no requirement for increasein the heating capacity of the plant but will effect a change in therelative distribution of supply to the radiators concerned and withoutof necessity causing any change in the supply of heating medium to thoseradiators whose valves remain as before. The possibility ofinterchanging the stop devices between any two radiators in the systemgives to the engineer in charge a wide choice as to the two particularvalves whose stop devices shall be interchanged. Naturally a record ofthe existing installation of stop devices in the diiferent valves willbe kept up to date Vto accord with all interchanging of the stop deviceswhich has been made in the system. It will be understood that inpractice, stop devices having as many gradations of relationship betweenthe casing heldins 52 or 53 and the bushingstop shoulders 54, 55 as arerequired may be employed, eight diierent constructions of stop bushingembcdyingeight dierent such gradations being found useful in practice.For convenience the stop bushings of each different construction may bestamped with suitable index numbers as a key to the degree of maximumport opening they will'permit.. Such degree may in different stages begreater or smaller Vthan the extent of port opening shown in Fig. 9.

Ittherefore becomes ,plain that my improved construction, nature, andrelationship of devices for changingthe capacity heating performance ofdifferent radiators selectively without unbalancing the system asawholegive rise to very desirable features which have not heretofore beenavailable in heating systems. First, because of the iiuid sealing effectof the inner packing ring 43, the stop bushings may be interchangedwhile the interior of cylindrical gate 42 and the valve passage 45 arefull of water at greater than atmospheric pressure thus making possiblethe removal of the valve cap 31 without draining the water from thesystem. Second, the effect of replacing one stop bushing with adiierently constructed bushing does not vary the angular range ofmovement R in Figs. 2 and 3 which is performed by the valve handle 51but only varies theclosed limit position C and the open limit position Oto which the handle and valve stem are permitted to turn `in relation tothe valve casing. As radiator valve handles are commonly round andwithout markings of any kind to indicate their rotative position andsince the range of permissible movement of the handle is. not varied,remaining always say, a half turn, it will be imperceptible to the userof any individual radiator that any change has been made in the controlvalve. Third, even by willful tinkering the occupant of a single roomhas no means available to change the iiow affecting characteristics ofthe stop bushing in a single radiator control valve because of theabsence of adjustable parts and because he will not have available adifferently constructed stop bushing with which to replace thatcontained in the valve. l

Additional features include, fourth, that the means herein proposed forrestricting or reducing the maximum opening of the valve ports in no wayprevents or interferes with the ability to adjust the size of theport'opening by movement of the valve handle to any desired setting lessthan the maximum port capacity determined by the stop bushing. Fifth, inthe absence of an extra supply of stopV bushings additional to thoseoriginally installed in the system, the engineer in charge is restrictedto interchanging the bushings between the different valves and cannot byan unwise use of a different aggregate of bushings disrupt the compositesizes of conduit passages for the circulating water or other heatingmedium in the system as a whole. Sixth, nevertheless when occasiondemands, by introducing new stop bushings into the system, changes inthe heating plant itself may be compensated for without repiping anypart of the system. Such changes might reside in the installation of anew boiler or heating unit of different heating capacity than the old,and in the introduction or elimination of apparatus for increasing thecirculation such as the circulating pump 24.

It will be noted that Figs. 2 and 3 are views looking downwardly uponthe valve in which the valve handle turns clockwise vto close the valveand counterclockwise to open the valve. In Figs. 7 to 14, inclusive,this direction of turning of the parts is reversed because thesesectional views are representations of the parts in each case lookingupwardly with respect to the valve handle.

Having described the present improvements in one structural form for thepurpose of explaining Ythe principles underlying the invention, it willbe understood that many modifications of the structure described andmany possible substitutes therefor will be suggested to those skilled inthe art by the presentV disclosure. The appended claims are intended toembrace all equivalents, modifications and substitutes which come withinthe scope of the invention and fall fairly within their terms. I

' I claim: l

v1. The method of inverting the proportional amounts of a circulatingheat conveying medium permitted to flow in a heating system throughdilerent conduits each incorporating a movable port control gate and anassociated device removable from the conduit, which consists in fixedlypredetermining by the use of said devices diierent locations of thepermissible ranges of back and forth movement of said gates relative totheir respective conduits, and then interchanging the said devicesbetween said different conduits in a manner to invert the predeterminedeiect of said devices upon said locations of said permissible ranges ofgate movement.

2. The method of inverting the proportional amounts of a circulatingheat conveying medium permitted to ow through diierent radiators in aheating system respectively controlled by flow modulating valves eachhaving a separate operating handle and an associated device removablefrom the valve, which consists in ixedly predetermining by the use ofsaid removable devices diierent rotary locations of the permissiblerange of valve opening and closing movements of said handles in relationto their respective values, and then interchanging sai-d devices betweensaid valves.

3. A circulating fluid heating system including in combination, a sourceof fluid flow, conduits constructed to form a plurality of loop-likefluid passageways connected to receive iluid owing from said source andto return the uid thereto, a flow throttling gate turnably mounted ineach of said passageways and having a manually operable` extensionreaching to the outside of the conduit structure which forms thepassageway, and' stop means mechanically associated with each conduitstructure in a manner to limit the turning of each of said gates to axed range of back and forth movement restricted by said stop means to asingle possible rotary location relative to its passageway said locationbeing diierent in respectively different passageways and said stop meansembodying devices constructed to be mutually interchangeable between atleast two of said passageways.

4. A heating system comprising in combination, means for circulating aheating medium, a plurality of loops of conduit connected to formdiierentl passageways for receiving a il'ow of said medium from saidmeans and for returning it thereto, space immuring structure forming achamber adjacent to and oiset from the passageway in each of said loopsof conduit, a flow governing baiiie movably mounted in each of saiddifferent passageways having an operating element extending into thechamber adjacent thereto, devices located respectively in each of saidchambers constructed and arranged cooperatively with the respectiveoperating elements of said baflies to limit to a single xed point inrelation to a given passageway but to diierent points in relation torespectively different passageways the flow increas ing movements ofsaid baiiles, and means for stationing said devices respectively in saidchambers in a manner to permit the selective interchanging of differentdevices between different chambers.

5. In combination with a heating system as dened in claim 4, meansconstructed and arranged to effect a iluid tight seal between each ofthe said chambers and its adjacent conduit passageway in a manner topreclude escape of the said heating medium from said passageway intosaid chamber, thereby to enable said devices to be interchanged whilesaid passageways are full of the heating medium.

6. In a heating system including heating apparatus, pipes for conductinga flow of heat con veying fluid and radiators connected in the system atrespectively diierent distances from the heating apparatus; incombination, a plurality of uid i'low control valves piped to controlrespectively different radiators, each valve including a handle-operatedfluid ow control gate turnable through a like range of movement betweenclosed and open limit positions, and devices similarly constructed incertain portions enabling them to be interchanged between said valvesand differently constructed in other portions enabling them topredetermine a single definite limit position for the said control gatedilerently located in difierent valves in relation to the bodies of saidvalves.

'7. In a fluid circulating heating system for building interiorsincluding a plurality of radiators, in combination, a plurality ofvalves for separately controlling the flow of uid through respectivelydifferent radiators, each of said valves including a gate operative tocontrol the passage for uid through-the valve, a stem in each of saidvalves connected to operate its gate and arranged to be turnable througha like range of movement in each of said valves between a limit positionfor closing said pass-age and a limit position for opening said passage,and devices constructed and arranged to be selectively interchangeablebetween said valves and operatively associated respectively with thestems thereof in a manner to predetermine and restrict said limitpositions to constant but diiering locations in each of said valves.

8. In a uid circulating heating system for building interiors, thecombination defined in claim 7 in which the said devices are immuredwithin the valve in a manner to be concealed from the user of the valveand inaccessible without the use of tools.

9. A heating system including, in combination, conduits lled with wateradapted to circulate through the system under a common head of greaterthan atmospheric pressure, means to heat said water and cause it to flowthrough the passageways of different sections of said conduits, manuallyoperable ow control gates turnably mounted respectively within saidpassageways each of said gates containing a flow control port turnableinto register with its conduit passageway, and means for varying theproportional distribution of water ow through different sections of saidconduits embodying a device mechanically associated with each of saidgates constructed and arranged cooperatively therewith to limit to asingle predetermined size the portion of said flow control port that canbe turned into register with the conduit passageway, said devices beingmutually interchangeable and diiering in construction in a manner topermit a diieren-t portion of the respectively different flow controlports to be aligned with their respective passageways.

l0. A water heating system as dened in claim 9, in which each of thesaid gates has a manual operating element extending outside the conduitpassageway, and in which each of the said devices is located outside theconduit passageway in uid isolated relation to the water contained underpressure in said passageway.

11. In a heating system'n which aV heating medium is circulated throughloops of conduitl arranged to lead said medium from a common source ofheat through respectively diierent radiators and back to said source ofheat, in combination, at least two valve bodies connected inrespectively diierent loops of said conduit, a movable port controlmember in each of said valve bodies equipped with an operating handleexterior thereto, and stop devices respectively installed within saidvalve bodies in a removable manner and arranged to limit to a fxedlystationed range of port controlling movement the handle equipped membertherein, each of said stop devices being similarly constructed in oneportion thereof in a manner to establish each device in a like xedrelation to each body of the different valves, and each of said devicesbeing constructed dilerently from the other device in a, differentportion thereof for cooperating with said port control members in amanner to restrict the ports controlled thereby to openings of differentmaximum capacity in respectively diierent valve bodies, whereby themaximum capacities of port openings in two of said valves may berelatively inverted by interchanging said stop devices between saidvalves.

12. In a house heating system, the combination with a series ofpipe-connected radiator control v alveseach having a body and ahandle-rotated stem for opening and closing the va1ve,of a seriesl ofstop members constructed to be interchangeably applied to said valvesrespectively and further constructed and arranged to limit the range ofback and forth turning movement of the chamber contained valve stem toless than S60-degrees, said stop members differing in construction fromone another in a manner to predetermine a, single fixed location oi saidrange of turning movement differently related to the valve body ofrespectively diflerent valves in the system.

13. In a house heating system, the combination with a series ofpipe-connected radiator control valves each having a body containing achamber and each having a handle-rotated stem extending into saidchamber for opening and closing the valve, of a series of stop membersconstructed to be interchangeably insertable and xedly held within therespective chambers of said valves and further constructed and arrangedto limit the range of back and forth turning movement of the chambercontained valve stem to less than 360- degrees said stop membersdiffering in construction from one another in a manner to predetermine asingle fixed location of said range of turning movement differentlyrelated to the valve body oi respectively different valves in thesystem.

GEORGE J. BELKNAP.

